GitLab

audio::UserInputMonitor overrides audio::UserInputMonitor::GetKeyPressCount() to read key press
count (computed in browser process) from shared memory. Read only handle to key press count shmem
is passed over IPC on audio service input stream creation.

Design doc: https://docs.google.com/document/d/1GHL4uMlIFox2eAqsjUQVA8eJ7HYU3g2AoyAqyx3pxMA/edit?usp=sharing

Notes:
- Browser side implementation of key press count share memory, and  wrapping of memory handle
  into a Mojo handle will be added in dependent CL https://crrev.com/c/1025754.
- UserInputMonitor is enabled in MojoAudioInputStreamObserver constructor, when a stream is created,
  and disabled on connection error, called when the observed stream is destroyed.
- audio:: and media:: UserInputMonitor implementations inherit from media::UserInputMonitorBase in
  order to keep media::AudioInputController unchanged for now. Inheritance will be removed when
  switching to audio service input streams.

Streams design diagram: http://drawings/1_ZIKj6lihGKRjq4Mflduitmkn_REqpHFeqVNelBGHHk

Bug: 828864
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I0219494d73df2fd275d2b7ccb5bf01f81a1ff11c
Reviewed-on: https://chromium-review.googlesource.com/1011605
Commit-Queue: Marina Ciocea <marinaciocea@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Reviewed-by: Max Morin <maxmorin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553967}